415 research outputs found
Extended Molecular Gas Reservoirs are common in a distant galaxy cluster
This presentation was delivered by Zhengyi Chen at the "FIRST STRUCTURES IN THE UNIVERSE 2023" workshop in Paris. The original abstract for this presentation is as follows:
"It is clear that galaxies in local clusters are different from those in the field. Environment must play an important role in shaping the ensemble of galaxies. However, we do not yet know when these physical processes are initiated and what mechanisms directly impact how galaxies evolve. We are using the Australian Telescope Compact Array (ATCA) to study the role of environment on the molecular gas content, the fuel of star formation, of distant, star- forming galaxies. These massive, heavily dust obscured sources are the likely progenitors of elliptical galaxies which dominate the light in local galaxy clusters. The cold molecular gas is the most direct ingredient of star-formation, and is commonly traced by carbon monoxide (CO). Galaxy protoclusters, where circumgalactic medium (CGM) is accreting to the web nodes through the filaments, are ideal laboratories to study the galaxy-CGM co-evolution characterized by inflow (e.g., gas accretion and recycle) and outflow processes. Within the ATCA large program COALAS (CO ATCA Legacy Archive of Star-forming Galaxies), we searched - via the ground-transition CO(1-0) - for cold molecular gas emission in the Spi- derweb galaxy protocluster, surrounding the radio galaxy MRC1138-262. We obtained a robust sample of several dozen CO(1-0) detections physically related to the targeted galaxy cluster in formation. This is the largest sample of molecular gas measurements in a distant cluster to date. Through a pilot study, we discovered two massive extended CO gas reser- voirs (40 and 70 kpc large) in the Spiderweb protocluster. We speculate that such gigantic molecular-phase CGM could be an important driver for the built-up of massive galaxies in large scale structures. Triggered by our findings and aiming to test our hypothesis, we started the first systematic search for extended CGM within the 46 CO emitters physically related to the Spiderweb protocluster. In our contribution, we will introduce the method we used for searching, discuss the frequency of this phenomena, study the environmental impact, compare it with the literature and conclude on the mass assembly in large scale structures.
Crystal structure of azilsartan methyl ester ethyl acetate hemisolvate
We gratefully acknowledge financial support from the NSFC (No. 21002009), the Scientific and Technological Project of Jiangsu Province (BY2014037–01), the Major Program for Natural Science Research of Jiangsu Colleges and Universities (12 K J A150002, 14 K J A150002) and the Qing Lan Project of Jiangsu Province.Peer reviewe
The substructure and halo population of the Double Cluster and Persei
In order to study the stellar population and possible substructures in the
outskirts of Double Cluster and Persei, we investigate using the
GAIA DR2 data a sky area of about 7.5 degrees in radius around the Double
Cluster cores. We identify member stars using various criteria, including their
kinematics (viz, proper motion), individual parallaxes, as well as photometric
properties. A total of 2186 member stars in the parameter space were identified
as members. Based on the spatial distribution of the member stars, we find an
extended halo structure of and Persei, about 6 - 8 times larger than
their core radii. We report the discovery of filamentary substructures
extending to about 200 pc away from the Double Cluster. The tangential
velocities of these distant substructures suggest that they are more likely to
be the remnants of primordial structures, instead of a tidally disrupted stream
from the cluster cores. Moreover, the internal kinematic analysis indicates
that halo stars seems to be experiencing a dynamic stretching in the RA
direction, while the impact of the core components is relatively negligible.
This work also suggests that the physical scale and internal motions of young
massive star clusters may be more complex than previously thought.Comment: 9 pagges, 9 figures, Accecpted to A&
Effects of temperature on photosynthetic performance and nitrate reductase activity in vivo assay in Gracilariopsis lemaneiformis (Rhodophyta)
Gracilariopsis lemaneiformis is an economically-valued species and widely cultured in China at present. After being acclimated to different growth temperatures (15, 20, 25, and 30 degrees C) for 7 days, the relative growth rate (RGR), nitrate reductase activity, soluble protein content and chlorophyll a fluorescence of G. lemaneiformis were examined. Results show that RGR was markedly affected by temperature especially at 20 degrees C at which G. lemaneiformis exhibited the highest effective quantum yield of PSII [Y(II)] and light-saturated electron transport rate (ETRmax), but the lowest non-photochemical quenching. Irrespective of growth temperature, the nitrate reductase activity increased with the incubation temperature from 15 to 30 degrees C. In addition, the greatest nitrate reductase activity was found in the thalli grown at 20 degrees C. The value of temperature coefficient Q10 of alga cultured in 15 degrees C was the greatest among those of other temperatures tested. Results indicate that the optimum temperature for nitrate reductase synthesis was relatively lower than that for nitrate reductase activity, and the relationship among growth, photosynthesis, and nitrate reductase activity showed that the optimum temperature for activity of nitrate reductase in vivo assay should be the same to the optimal growth temperature
V3D: Video Diffusion Models are Effective 3D Generators
Automatic 3D generation has recently attracted widespread attention. Recent
methods have greatly accelerated the generation speed, but usually produce
less-detailed objects due to limited model capacity or 3D data. Motivated by
recent advancements in video diffusion models, we introduce V3D, which
leverages the world simulation capacity of pre-trained video diffusion models
to facilitate 3D generation. To fully unleash the potential of video diffusion
to perceive the 3D world, we further introduce geometrical consistency prior
and extend the video diffusion model to a multi-view consistent 3D generator.
Benefiting from this, the state-of-the-art video diffusion model could be
fine-tuned to generate 360degree orbit frames surrounding an object given a
single image. With our tailored reconstruction pipelines, we can generate
high-quality meshes or 3D Gaussians within 3 minutes. Furthermore, our method
can be extended to scene-level novel view synthesis, achieving precise control
over the camera path with sparse input views. Extensive experiments demonstrate
the superior performance of the proposed approach, especially in terms of
generation quality and multi-view consistency. Our code is available at
https://github.com/heheyas/V3DComment: Code available at https://github.com/heheyas/V3D Project page:
https://heheyas.github.io/V3D
Effect of directional solidification rate on the microstructure and properties of deformation-processed Cu-7Cr-0.1Ag in situ composites
The influence of directional solidification rate on the microstructure, mechanical properties and conductivity of deformation-processed Cu-7Cr-0.1Ag in situ composites produced by thermo-mechanical processing was systematically investigated. The microstructure was analyzed by optical microscopy and scanning electronic microscopy. The mechanical properties and conductivity were evaluated by tensile-testing machine and micro-ohmmeter, respectively. The results indicate that the size, shape and distribution of second-phase Cr grains are significantly different in the Cu-7Cr-0.1Ag alloys with different growth rates. At a growth rate of 200 μm s-1, the Cr grains transform into fine Cr fiber-like grains parallel to the pulling direction from the Cr dendrites. The tensile strength of the Cu-7Cr-0.1Ag in situ composites from the directional solidification (DS) alloys is significantly higher than that from the as-cast alloy, while the conductivity of the in situ composites from the DS alloys is slightly lower than that from the as-cast alloy. The following combinations of tensile strength, elongation to fracture and conductivity of the Cu-7Cr-0.1Ag in situ composites from the DS alloy with a growth rate of 200 μm s-1 and a cumulative cold deformation strain of 8 after isochronic aging treatment for 1 h can be obtained respectively as: (i) 1067 MPa, 2.9% and 74.9% IACS; or (ii) 1018 MPa, 3.0%, and 76.0% IACS or (iii) 906 MPa, 3.3% and 77.6% IACS
3,9-Di-tert-butyl-2,4,8,10-tetraoxaspiro[5.5]undecane
The title compound, C15H28O4, was prepared by the condensation of pivalaldehyde with pentaerythritol. In the crystal, the two halves of the molecule are related by a crystallographic twofold rotation axis passing through the central spiro-C atom. The two non-planar six-membered heterocycles both adopt chair conformations with the two tert-butyl groups both located in the equatorial positions
Activation of Protein Serine/Threonine Phosphatase PP2Cα Efficiently Prevents Liver Fibrosis
Over-activation of TGFβ signaling pathway and uncontrolled cell proliferation of hepatic stellate cells (HSCs) play pivotal roles in liver fibrogenesis, while the protein serine/threonine phosphatase PP2Cα was reported to negatively regulate TGFβ signaling pathway and cell cycle. Our study aimed to investigate the role of PP2Cα in liver fibrogenesis.The effects of PP2Cα activation on liver fibrosis were investigated in human HSCs and primary rat HSCs in vitro using western blotting, real-time PCR, nuclear translocation, cell viability and cell cycle analyses. The antifibrogenic effects in carbon tetrachloride (CCl(4))- and bile duct ligation (BDL)-induced mice in vivo were assessed using biochemical, histological and immunohistochemical analyses. The results demonstrated that activation of PP2Cα by overexpression or the new discovered small molecular activator NPLC0393 terminated TGFβ-Smad3 and TGFβ-p38 signaling pathways, induced cell cycle arrest in HSCs and decreased α-smooth muscle actin (α-SMA) expression, collagen deposition and hepatic hydroxyproline (HYP) level in CCl(4)- and BDL-induced mice.Our findings suggested that PP2Cα activation might be an attractive new strategy for treating liver fibrosis while the small molecular activator NPLC0393 might represent a lead compound for antifibrogenic drug development. Moreover, our study might provide the first evidence for the role of PP2C family members in the fibrotic disease
Robust Classification via a Single Diffusion Model
Recently, diffusion models have been successfully applied to improving
adversarial robustness of image classifiers by purifying the adversarial noises
or generating realistic data for adversarial training. However, the
diffusion-based purification can be evaded by stronger adaptive attacks while
adversarial training does not perform well under unseen threats, exhibiting
inevitable limitations of these methods. To better harness the expressive power
of diffusion models, in this paper we propose Robust Diffusion Classifier
(RDC), a generative classifier that is constructed from a pre-trained diffusion
model to be adversarially robust. Our method first maximizes the data
likelihood of a given input and then predicts the class probabilities of the
optimized input using the conditional likelihood of the diffusion model through
Bayes' theorem. Since our method does not require training on particular
adversarial attacks, we demonstrate that it is more generalizable to defend
against multiple unseen threats. In particular, RDC achieves robust
accuracy against norm-bounded perturbations with
on CIFAR-10, surpassing the previous state-of-the-art
adversarial training models by . The findings highlight the potential
of generative classifiers by employing diffusion models for adversarial
robustness compared with the commonly studied discriminative classifiers
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